The Castell Malgwyn canal was constructed to convey water to power the Tinplate works at Castell Malgwyn. Its construction was passed by an act of Parliament in 1772 and although the term 'canal' is used in a number of documentary sources, there is no indication that the waterway was ever intended to be navigable and was for water-supply purposes only, conveying water from the River Teifi and to a lesser extent the Morgenau.